Development of novel thin film composite reverse osmosis membranes for desalination

Microporous Polyetherimide (PEI) membranes were prepared by wet phase inversion at different temperatures. The thin film composites (TFC) of polyamide on microporous PEI were prepared using meta-Phenylenediamine (MPD) and 1,3,5-Benzenetricarbonyl chloride (BTC). The ATR FTIR characterization showed the formation of polyamide (PA) on microporous PEI membrane, whereas scanning electron microscopy (SEM) revealed that a thin film of polyamide is formed on microporous PEI. The cross-sectional SEM of PEI prepared at 60 °C, showed finger like morphology and sparingly distributed balloon like morphology for PEI synthesized at 80 °C. The performance of PEI membranes and PA TFCs were ascertained by studying permeation of water and rejection of sodium chloride by reverse osmosis. The polyamide TFC with hydrophobic PEI support structures exhibited permeation of 28 to 50 lm-2h-1, with 98 – 95 % 2000 ppm NaCl rejection at 60 bar pressure

Development of a novel tailored ion-imprinted polymer for recovery of lithium and strontium from reverse osmosis concentrated brine

This study aims to prepare ion-imprinted polymer (IIP) with the benefit of a metal-based sorbent, which is fabricated to selectively adsorb lithium (Li+) from aqueous solutions, and in an attempt to remove strontium (Sr2+). The adsorption processes were carried out at different pH values, initial concentrations, and temperatures, to optimize the experimental conditions, with the use of response surface methodology (RSM). The seawater reverse osmosis (SWRO) brine was physically and chemically characterized, and the physicochemical characterization of the prepared IIP before and after adsorption was also performed using different spectroscopic methods. The adsorption capacity for Li+ and Sr2+ from SWRO brine was evaluated, and the reusability of IIP was investigated using adsorption–desorption cycles. The results showed that the IIP was efficient to remove Li+ but not Sr2+, and it follows Freundlich adsorption isotherms models. The analysis revealed a significant concentration of minerals in the brine sample It also revealed a low concentration of trace metals, like Ba (0.16 mg/L), Zn (0.845 mg/L), Fe (1.31 mg/L), Cu (1.165 mg/L), Pb (1.505 mg/L), and V (3.88 mg/L), except Li and Sr which shows a higher concentration of 43.32 mg/L and 16.93 mg/L respectively. pH 10 was selected to be the optimum pH for the adsorption isotherm experiments, as it was the highest efficient pH to adsorb Li+ and Sr2+. The thermodynamics study revealed that the adsorption of Li+ on the IIP favored exothermic conditions. It was noticed that the maximum adsorption capacity (Qm) was increased as the temperature rise from 714.3 mg/g at 25 °C to 2500 mg/g at 45 °C. The Li+ desorption results show that 94.03% − 94.71% of the ions were recovered, while the Sr2+ desorption results show that 96.35% − 96.56% of the ions were recovered. The efficiency of IIP to adsorb lithium and strontium from brine shows that the adsorption removal% of Li+ was between 84.21% and 84.68%, while the adsorption removal% of Sr2+ was between 3.83% and 10%. The cost analysis for IIP preparation was 2 USD/g.This work was made possible by Qatar University collaborative internal grant [QUCG-CAS-20/21-2]. The findings achieved herein are solely the responsibility of the author[s]. The ICP-MS, SEM, and TEM were accomplished in the Central Laboratories Unit, Qatar University. XRD was accomplished in the Center of Advanced Materials, Qatar University. XPS was accomplished in the Gas Processing Center, Qatar University. Open Access funding provided by the Qatar National Library

Health risk assessment of methyl mercury from fish consumption in a sample of adult Qatari residents

Fish constitutes an essential source of high-quality protein and is, at the same time, the source of exposure to many hazardous contaminants, namely mercury and methyl mercury (MeHg). This study aims at assessing the risk that MeHg poses to the health of adult Qatari residents through fish consumption. Data on fish consumption were collected using a self-administered online survey composed of three sections that collected information about the fish-eating patterns of the participants. The fish species that were reported to be consumed by ≥ 3% of the respondents were sampled and analyzed for their total mercury (T-Hg) content levels. MeHg concentrations were derived from T-Hg content levels using a scenario-based approach. Disaggregated fish consumption and contamination data were combined using the deterministic approach to estimate MeHg intakes. The average, 75th, and 95th percentiles of the MeHg intake estimates were determined and compared to the tolerable weekly intake (TWI) set by the European Food Safety Agency (EFSA) (1.3 μg·kg−1·w−1). All fish samples contained T-Hg at levels ˂ 0.3–0.5 µg/g with a mean value of 0.077 µg/g. The study population had an average fish consumption of 736.0 g/week. The average estimated weekly intakes of MeHg exceeded TWI for some fish consumers including females of childbearing age and those following a high-protein diet. Our study highlights the need to establish regulatory guidelines and dietary advice based on risk/benefit ratio.The study was supported by the central Food laboratory of the ministry of public health.Scopu

Hydrogeochemical characterization and quality evaluation of groundwater suitability for domestic and agricultural uses in the state of Qatar

This study aims to investigate the groundwater (GW) quality in Qatar to be utilized in domestic and agricultural uses. The integrated physiochemical analysis along with hydrochemical faces analysis, geochemical modeling, statistical and geostatistical analysis was conducted. The results showed that the GW samples mainly have the following cations Na+ > Ca2+ > Mg2+ >K+ abundantly, while Cl− > SO42− > HCO3− > NO3− were the main anions. The obtained analytical values of the GW samples were plotted on Piper, Schoeller, Ternary, Ludwig Langelier, Giggenbach Triangle, Durov, and stiff graphs. The hydrogeochemical facies and the obtained graphs confirmed that most of the analyzed GW samples fall into two types of water namely calcium-chloride-type (SO4–Cl and Ca–Mg) and sodium-chloride-type (SO4–Cl and Na–K). Three principal components were yielded from the principal component analysis (PCA), which are the first principal component (PC1), second principal component (PC2), and third principal component (PC3) with ≥1 Eigenvalues, and total variance of 49, 31, and 19.9%, respectively. A positive loading of Mg, Th, Sr, Ca, TDS, SO4, Li, Cl, F, Br, Cd, K, Ba, and Na has been shown by the PC1; representing the factors which are contributing to the high salinity of the GW due to the salt water intrusion and the mineralization of rocks and soil which is supported by the water type classification and saturation indices. The PC2 showed a negative loading of U, Al, Se, Mo, Mg, and temperature, which could be associated with a localized sedimentary depositional or hydrogeochemical environment. The PC3 showed a positive loading of Ni, Zn, Be, pH, Cu, Co, Fe, B, V, and TOC, which indicates the dissolution and precipitation (reducing and oxidizing factor) such as iron which is a redox-sensitive variable.Scopu

Development of industrially viable geopolymers from treated petroleum fly ash

This paper investigates the development of stable geopolymers using petroleum fly ash with high compressive strength and water absorption to promote cleaner production, sustainability, and recycling of waste. The paper provided detailed characterizations of the petroleum fly ash, which involved the determination of the particle size diameter, density, surface area, pore-volume, mineralogical identification of recording X-ray diffraction pattern, X-ray fluorescence, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscope. Moreover, metals leachability from the petroleum fly ash using different extracting agents, namely H2SO4, H3PO4, (NH4)2SO4, NH4NO3, and NH4O2CCO2H was also considered. Five geopolymers were prepared using different amounts of petroleum fly ash to assess the influence of petroleum fly ash on the final performance of the prepared geopolymers. The results revealed that the petroleum fly ash was carbonaceous in nature and rich in vanadium oxide and nickel oxide with low in SiO2 and Al2O3. Furthermore, it was found that petroleum fly ash has a low calcium level. The maximum extraction values were 15.6% for V and 55.6% for Ni using H2SO4. All the prepared geopolymers displayed high compressive strength for longer curing times, and the water absorption properties of all geopolymers were improved by incorporating more petroleum fly ash. Increasing the petroleum fly ash from 0 vol% to 61 vol% increased the water absorption value from 6.6 to 13.3 wt% for the samples collected after 28 days of curing. It was concluded that the petroleum fly ash did tend to form successful stable geopolymers with high compressive strength and water absorption.Scopu

Recent developments and advancements in graphene-based technologies for oil spill cleanup and oil-water separation processes

The vast demand for petroleum industry products led to the increased production of oily wastewaters and has led to many possible separation technologies. In addition to production-related oily wastewater, direct oil spills are associated with detrimental effects on the local ecosystems. Accordingly, this review paper aims to tackle the oil spill cleanup issue as well as water separation by providing a wide range of graphene-based technologies. These include graphene-based membranes; graphene sponges; graphene-decorated meshes; graphene hydrogels; graphene aerogels; graphene foam; and graphene-coated cotton. Sponges and aerogels modified by graphene and reduced graphene oxide demonstrated effective oil water separation owing to their superhydrophobic/superoleophilic properties. In addition, oil particles are intercepted while allowing water molecules to penetrate the graphene-oxide-coated metal meshes and membranes thanks to their superhydrophilic/underwater superoleophobic properties. Finally, we offer future perspectives on oil water separation that are hindering the advancements of such technologies and their large-scale applications.Scopu

Spectral and Structural Properties of High-Quality Reduced Graphene Oxide Produced via a Simple Approach Using Tetraethylenepentamine

A simple temperature-assisted solution interaction technique was used to functionalize and reduce graphene oxide (GO) using tetraethylenepentamine (TEPA) with less chemicals, low temperature, and without using other reducing agents. GO nanosheets, produced using a modified Hummers? method, were functionalized using two different GO:TEPA ratios (1:5 and 1:10). The reduction of GO was evaluated and confirmed by different spectroscopic and microscopic techniques. The FTIR and XPS spectra revealed that most of the oxygenated groups of GO were reduced. The emergence of amide groups in the XPS survey of the rGO-TEPA samples confirmed the successful reaction of TEPA with the carboxyl groups on the edges of GO. The replacement of the oxygenated groups increased the carbon/oxygen (C/O) ratio of GO by approximately 60%, suggesting a good reduction degree. It was found that the I2D/ID+D? ratio and the relative intensity of the D?? band clearly increased after the reduction reaction, suggesting that these bands are good estimators for the reduction degree of GO. The morphological structure of GO was also affected by the reaction with TEPA, which was confirmed by SEM and TEM images. The TEM images showed that the transparent GO sheets became denser and opaque after functionalization with TEPA, indicating an increase in the stacking level of the GO sheets. This was further confirmed by the XRD analysis, which showed a clear decrease in the d-spacing, caused by the removal of oxygenated groups during the reduction reaction.Scopu

Kinetics of biodegradation of diethylketone by Arthrobacter viscosus

The performance of an Arthrobacter viscosus culture to remove diethylketone from aqueous solutions was evaluated. The effect of initial concentration of diethylketone on the growth of the bacteria was evaluated for the range of concentration between 0 and 4.8 g/l, aiming to evaluate a possible toxicological effect. The maximum specific growth rate achieved is 0.221 h-1 at 1.6 g/l of initial diethylketone concentration, suggesting that for higher concentrations an inhibitory effect on the growth occurs. The removal percentages obtained were approximately 88%, for all the initial concentrations tested. The kinetic parameters were estimated using four growth kinetic models for biodegradation of organic compounds available in the literature. The experimental data found is well fitted by the Haldane model (R2 = 1) as compared to Monod model (R2 = 0.99), Powell (R2 = 0.82) and Loung model (R2 = 0.95). The biodegradation of diethylketone using concentrated biomass was studied for an initial diethylketone concentration ranging from 0.8–3.9 g/l in a batch with recirculation mode of operation. The biodegradation rate found followed the pseudo-second order kinetics and the resulting kinetic parameters are reported. The removal percentages obtained were approximately 100%, for all the initial concentrations tested, suggesting that the increment on the biomass concentration allows better results in terms of removal of diethylketone. This study showed that these bacteria are very effective for the removal of diethylketone from aqueous solutions.The authors would like to gratefully acknowledge the financial support of this project by the Fundacao para a Ciencia e Tecnologia (FCT), Ministerio da Ciencia e Tecnologia, Portugal and Fundo Social Europeu (FSE). Cristina Quintelas thanks FCT for a Post-Doc grant